Re: The warming trend & extinction events & ex-astra expl.

Timo Niroma (
13 Jul 1996 00:11:07 GMT

In article <>, p3voices <> says:
>Timo Niroma:
> That's a lot of interesting data and analysis you have compiled on
>temperature changes and sunspot counts. Maybe you are on to something
>here, but please take caution - over time the methodologies of acquiring
>this data have changed. Temperature records are somewhat suspect because
> Now to engage in <wild> speculation, and assuming your analysis is
>on target, perhaps a sudden and quite large increase in sunspot count
>about 11600 years ago could have ended the ice age, by increasing the
>solar output. While we like to believe the sun is a constant energy
>source, we have no good observational data to proove this is true over
> Now to move to my point:
> Timo, it seems you are suggesting that meteors caused one climactic
>change (end of most recent ice age) and that sunspots cause another
>(recent history)? I'd suggest that you can't have it both ways, and that

1) It is possible that the temperature measurement were not as accurate in the 19th
century as they are in the 20th century. I have however no reason to doubt that the
possible inaccuracy was systematic or so great as to make the trends invaluable or

2) That I admit that because Helsinki has during this 170 years period grown from a
small town to a town of a half million people, that can have had a slight warming
tendency. However the place of measurement is in a park, in fact in a botanical
garden near a small lake. There was in the 19th century and in the early part of the
20th century a sugar factory on the other side of the like which is there any more.
If it caused some warming it should have been felt from about 1850 to 1950.

3) Helsinki situates ideally from the meteorological point of view. It's a seaside
town just on the border of the continental Russian climate and the watery Atlantic
Ocean plus on the border of the south winds from Mediterranian and the north winds
from North Pole.

4) It is true that the Zurich sunspot numbers are not as reliable as the Solar Flux
for example from Pentic, but unfortunately the 2800 MHz measurements are available
only since 1947, when the sunspot numbers from Zurich are available on daily basis
from 1818 and on monthly basis since 1749. And I know that the way they are counted
was developed in the 1840s, so values before that are calibrated.

5) Despite of these unfortunate inaccuracies I think the trends, if not every
absolute value, are rather reliable.

6) The sudden catastrophic warming that happened 11600 and ended the ice age (by
definition) has a very different nature than the supposed general warming trend
during, I would dare to say, the last 200 years, with that little exception from
1895 to 1920. So I don't see why I can't use two different hypotheses. They were two
different kinds of warmings.

7) I admit that Sun is a variable star, and because the Milankowicz cycles don't
explain the sudden changes, and it seems likely, that there even is not a 100,000
year cycle, at least not for the reason Milankowicz suggested, I keep open the
possibility that the Sun's ireegularity is a third factor that has to do with ice
ages, big ones, and small ones.

8) Now we have three explanations for these trends, that are not exclusive: Sun's
variability, Milankowicz cycles, and asteroid or comet hits. All that we now from
the end of the ice age points as to my mind that the impact theory is the likeliest,
although the other two may have had some influence.

9) There is still a fourth variable: interstellar clouds. But we know too little
about them to say anything more than that they can cause an ice age.